Later on Monday, Apple will begin rolling out WatchOS 5 – the operating system that powers the increasingly-popular Apple Watch.

The rollout of WatchOS 5 comes about a week ahead of the launch of the Apple Watch Series 4, the next generation of the wearable device. But if you already own an Apple Watch Series 1 or Series 3, take heart: WatchOS 5 is bringing some new features and tweaks to your existing device.

Most of the new WatchOS 5 features were already announced by Apple during its WWDC event back in June. However, Apple had a few surprises in store at its big iPhone release event last week; namely, a few new watch faces, and a new feature – unique to the new Series 4 – for taking ECG (electrocardiogram) heart readings.

WatchOS 5 will be available for the Apple Watch Series 1 and newer models. This means that, unfortunately, WatchOS 5 won’t be available for the original Apple Watch (the so-called Series 0), which was released in 2015.

For those who get WatchOS 5, though, take heart, because your Apple Watch is getting a lot smarter.

Check out all the new features coming to Apple Watch with WatchOS 5:

The Apple Watch Series 4 has an updated design and features compared to older models.

Foto: sourceJustin Sullivan/Getty Images

Apple freshened up the Apple Watch design with thinner bezels, new larger sizes, a digital crown with haptic feedback, and a variety of other updates, like extra sensors, new materials, and an upgraded chip for performance.

Chief among the new features in the Series 4: The ability to take an electrocardiogram (ECG), which can help detect heart conditions early.

Foto: sourceApple

The new ECG feature in the Apple Watch Series 4 is usually found on medical devices used to detect atrial fibrillation, which is a heart condition that can lead to strokes. Apple says it's the first company to offer over-the-counter ECG readings (though opinions vary).

The ECG can potentially register the early signs of a stroke, and warn you to seek medical help before anything serious happens. Depending on the severity of what the ECG on the Apple Watch Series 4 detects, you can have the watch send an automatic emergency notification to a trusted contact.

The Apple Watch Series 4 registers your ECG through the newly designed crown when you press it for 30 seconds. Apple says the ECG app is coming later this year - again, only for the Apple Watch Series 4. Sorry, owners of older devices.

The new Apple Watch Series 4 can also detect when you've taken a fall.

Foto: sourceApple

With the Apple Watch Series 4's new sensors and gyroscope, it can detect when you've taken a fall, and you can set it to make an emergency call if you're immobile for one minute afterwards.

Everything else in WatchOS 5 is coming to all Apple Watch Series 1, Series 3, and Series 4 watches. For instance, existing watches will get the ability to sense when your heart rate is too low.

Foto: sourceApple

It can also detect other irregular heart rhythms - like a pulse that's slower than usual. This is detected by the optical heard sensor on the Apple Watch.

New watch faces.

Foto: sourceJustin Sullivan/Getty Images

Apple announced new watch faces, including one with up to eight customizable complications, or special features.

Interactive notifications

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Instead of simply telling you things, notifications will be more interactive in WatchOS 5.

Some examples Apple showed off included checking in to flights and checking flight details in the Lufthansa app, rating your car ride and paying with Apple Pay, and extending restaurant reservations up to 30 minutes from the Yelp app.

Siri gets smarter

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Siri on WatchOS 5 will give you live sports scores, commute time to home or work, or your heart rate.

Siri Shortcuts will let you enable often-used activities based on the time you usually use them when you raise your Watch, like turning on smart light bulbs when you get home from work, playing music when you leave work, or starting a walk.

Plus, third-party apps can appear on the popular Siri watch face, which presents you with contextual information, when and as you need it.

You can view websites on the Apple Watch with WatchOS 5

Foto: sourceApple

You can view web content on the Apple Watch and click on links in Mail or Messages.

You no longer need to say "Hey Siri"

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You can simply raise your wrist to give Siri commands. No other wake words required.

The Podcasts app finally comes to WatchOS 5

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You can finally listen to podcasts without your phone, as the Podcasts app finally hits the Apple Watch with WatchOS 5.

New app: Walkie Talkie

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You can have immediate conversations with your contacts, like you would with a walkie talkie. Hold the button to talk, and let go to listen.

Automatic workout detection

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WatchOS 5 will automatically detect when you've started a workout. Even if you start the workout mode after starting the activity, you'll get credit for what you've already done, retroactively.

It will also detect when you end your workout by sensing reduced movement or a lowered heart rate, and it'll make a suggestion to stop your workout tracking.

Challenge friends to seven day competitions

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In WatchOS 5, you'll be able to challenge friends to a seven-day activity competition. If they accept, you each try to win the week to close the rings and earn points by performing fitness activities, like running or hitting the gym. You earn one point for each percentage of a ring you close.

In the middle of a competition, progress is updated for both you and your friends. And you get an award badge if you win.

Rolling mile pace and cadence for running

Foto: sourceapple wwdc 2018

On top of the current and average pace you get now with the Watch, you'll get rolling mile pace tracking in WatchOS 5 (which shows how fast you ran the previous mile). You can set a custom pace alert, and the Apple Watch will tell you if you're under or over the pace you've set for yourself.

You'll also be able to count your steps per minute with cadence tracking.

New workout types: Yoga...

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The new Yoga workout mode works primarily through tracking your heart rate.

...and Hiking

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Add your student ID card to the Wallet app

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Adding a college student ID to your Watch running WatchOS 5 will let university students get access to dorms, dining halls, gyms and libraries, campus events, pay for things at shops or bookstores, pay for laundry and vending machines, and even register you class attendance.

Student IDs on the Apple Watch, as well as iPhones running iOS 12 will be available this fall, starting with Duke, Temple, Johns Hopkins, The University of Oklahoma, Santa Clara University, and The University of Alabama. More colleges and universities will get support for student ID implementation on Watch and iPhone "over time."